1. Field of the Invention
The present invention relates to solar cell modules including solar cell elements sealed with a sealing member and particularly relates to a solar cell module including an electric device for extracting electricity generated by solar cell elements.
2. Description of the Related Art
In general, solar cell assemblies include a plurality of solar cell elements, connected to each other, for generating electricity with a desired voltage and current. Such assemblies cannot be used under harsh outdoor conditions without sealing the solar cell elements. Therefore, the solar cell elements must be sealed with sealing members, whereby the assemblies are transformed into solar cell modules. The sealing members usually contain ethylene-vinyl acetate (EVA) copolymer. Front members, such as glass sheets or fluorine resin films, having high weather resistance and transparency are placed at the tops of light-receiving faces of the solar cell modules. On the other hand, rear members, such as fluorine resin films or polyester films, having high weather resistance and insulation performance are placed on the faces opposite to the light-receiving faces. In the solar cell modules, the solar cell elements sealed with the sealing member are placed between the front members and rear members.
In order to extract electricity from the solar cell modules, electrodes connected to the solar cell elements are usually routed out of the sealing members, the front members, or the rear members. Techniques for routing the electrodes are disclosed in some documents. In the technique disclosed in Japanese Patent Laid-Open No. 2000-243996, an opening is formed such that the opening extends through a sealing member and a rear member to electrodes, placed on the side close to a rear face of a solar cell module, for extracting electricity, and lead wires placed in the opening are each soldered to the corresponding electrodes. In the technique disclosed in Japanese Patent Laid-Open No. 7-263768 or 10-335682, a notch is formed in end sections of a front or rear member and a sealing member such that electrodes are exposed.
Electrodes routed outside must be electrically insulated securely. That is, rainwater, which causes an electrical breakdown in connections of the electrodes, must be prevented from penetrating the connections if a solar cell module is used under harsh outdoor conditions. Therefore, usually, the electrode connections are fully covered with a terminal box or a junction box referred to as a housing. The electrodes are connected to cable connectors, extending out of the terminal box, with terminal blocks or the like placed in the terminal box, whereby the electricity can be withdrawn. In order to prevent the corrosion of the electrodes and connections placed in the terminal box, and in order to maintain the water tightness of the exposed portions of the electrodes, the terminal box is usually filled with a silicone sealant or the like. FIGS. 9 and 10 each illustrate a solar cell module with the terminal box. Reference numeral 23 represents a terminal box, reference numeral 24 represents a silicone sealant, and reference numeral 25 represents a connector cable.
In view of workability, it can be preferable to avoid placing protrusions, for example, the terminal box and the like, on rear faces of solar cell modules. In recent years, for example, a building-integrated photovoltaic module functioning as a building material has been extensively developed because such a module is effective in reducing cost for manufacturing photovoltaic systems and has a good appearance when placed on buildings. In the module, in view of workability, it can be preferable to avoid placing a terminal box on the rear face of the module. In this case, electrodes must be routed out of a front member and a terminal box must be placed on the front member, which cannot be securely joined to the terminal box. Since the front member must have high weather resistance, the front member usually includes a glass sheet or a fluorine resin film. In particular, when the front member includes such a fluorine resin film, the terminal box cannot be securely joined to the fluorine resin film. Therefore, the terminal box may be peeled off from the fluorine resin film.
In order to reduce cost for manufacturing solar cell modules, attempts have been made to reduce the thickness of the modules. Therefore, sections for extracting electricity must be simplified. Since new solar cell modules, which are readily installed and have good appearance in common with the building-integrated solar cell module, are being developed, the following components are in demand: electrode-routing components and electric device-fixing components which do not impair the flatness of the rear faces when electric devices, for example, terminal boxes, are placed on the modules and which are helpful in simplifying manufacturing steps, improving the yield, and greatly reducing manufacturing cost thereby.